Drag Racers: Diagnostic/Critiquing please:

I posted this video in my generic build thread but really want more input than that thread would achieve.

My first time out in my new to me Mk6 Golf R, also it is currently my only registered and inspected vehicle so hard launches were out. 540TW tires (first problem), about 350awhp, BC Racing coilovers, slow as berkeley.

Vid:

Please analyze that run and let me know what you think.

I think I need 200TW tires, OR a guy behind me in an 11.2s 3.0 Mazda something said he bought street drag tires at Walmart for $126ea or something.

Additionally, I need to adjust the BCs better judging from the rocking at shifts in the video.

Lastly, I just need to learn how to drive the thing. I made my first 3 passes in it last night.

Honestly I think the car would be a beast in a roll race (class based). It's just no one does that around here.

Conclusion:

I have a car that is 150hp more than stock. Stock per C&D went 14.9s in the 1/4. I went ~14s, but I think there is a second to be had. I want to see 12.99s with tires and adjustments. I cannot blow the wheels off of it until I have one of my other POSs inspected.

Thoughts?

When I can I will put the other 2 runs up when my buddy sends me the vids.

Where is your power peak and where are you shifting?

What are your trap speeds vs. stock?  Trap speeds are power, ET is launching.

Sorry, but the video is useless... we can't even see the times/mph.  You need to post your timeslips so we can see what's actually happening.

Circled is me and I scribbled the type of car next to me on them:

1st:

2nd:

3rd:

Been shifting after 6k but before 7200. 7200 is bingdabingbingdabing rev limiter. Launched between 2 and 4k, bogged and blew E36 M3 tires off. I don't know power peak really but about 7k drops me into torque band.

Front wheel biased AWD? 

60' times are everything, so if you aren't at least optimizing your launch, you aren't gonna post a good ET. I usually hit 2.0 in my 2016 V6 Camaro.  I've run a best of 13.909 @ 100.75 mph.  The factory time for the (quicker) automatic is 13.7.  It's bone stock, except for the Hankook Ventus 500tw rated tires.  As of today, it has 71,000 miles, and it's my daily.  It's a little over an hour to either of the strips near me.  With your car being modified somewhat, I can understand your reluctance to launch hard, but stickier tires won't help if your not launching hard.  In fact, they might accelerate wear and tear on items like half-shafts and cv joints.

Didn't watch the vid as I'm not on Wi-Fi right this second, but I hope you avoided the water box.  Avoid even the littlest puddle, and don't even run your a/c in the staging lanes.

Did some checking and looks like it is front wheel biased.

Could do with adjusting how stiff the rear is (I used rubber coil spring spacers on my car) to reduce the rearward squat it has on launch which *should* assist in the 60' as well as some adjustments to tire pressures to the rear (increasing to reduce roll resistance gradually), could buy you a tenth or two and not the hardest thing to do, also easily reversible.

FWD bias, no AC, but I forever get told about windows up, no water box.

Coilovers: more stiff down rear and more stiff rebound on fronts?

Edit:I need to find out what torque my axles will hold...

Are you spinning the tires? (Not on wifi to watch video)

If you are, then maybe AWD isn't really working? If not spinning tires, you need to launch harder. 2.5second 60ft is why you're not 12.99. note how the 60ft impacts the ET in your timesheets.

Traction control?

MPH around 104 indicates about 300ish at the crank, assuming 3400lb.

I think a dyno operator was fudging numbers. You also probably got righteous heatsoak in the staging lanes, but not 150hp worth.

preach (dudeist priest) said:

FWD bias, no AC, but I forever get told about windows up, no water box.

Coilovers: more stiff down rear and more stiff rebound on fronts?

Edit:I need to find out what torque my axles will hold...

You want weight transfer to the rear.  Look at any purpose built drag car at launch, and most times they are picking up at least one front wheel.  They run really soft springs in the rear with low bound settings trying to get as much weight over the rear axle as possible. Obviously you want to keep all four tires on the ground with AWD, but the rear tires are going to have more traction available with the weight shifting rearward at launch.  Also, are you running a lot of camber?  If you have a lot in the rear, when the car squats, you may only have an inch and a half of tire width touching the ground.

I will preface this with the caveat that my experience is mostly on the build side and not a ton of seat time.  I used to build 10-second cars, but when I sit in the left seat, they are 11 or 12 second cars.

My guess is that the AWD is like many FWD-based AWD.  It's a FWD car that happens to have a wee little transfer case that sends 30% torque to the rear every once in a while.  They're great in rain and snow and fun in the twisties but at traction limits (like drag launches) they can get overwhelmed easily.

I dig why you don't want to break things, but your launch seems pretty timid.  The fear of breakage is real and I get it.  The launch is super key to getting the most forward acceleration before the tire leaves the second beam and getting the most you can by 60 feet.

Going back to my first paragraph... how experienced are you?  A massive part of ET and MPH is the ID-10-T variable behind the wheel.  Not saying you're a bad driver, it's just possible you're in a 13 second car and just need some runs under your belt until you can feel the fast.

BTW... with the exception of that one slow one, I'm totally jealous of your R/T.  I'm still in the .500s.  I had one .150 that was a total fluke last year at the challenge (where it doesn't matter anyway).  I'm too afraid of red lights.

Take a look at the graph below of a random car and forgive me if you already know this.  Notice how an acceleration curve is exponential.  Notice that the average acceleration in the first 5 seconds is around 5m/s2 and the acceleration in the 5-10 second range averages closer to 2.5m/s2.  Then from 10-15 seconds, it's only around 1.5m/s2.   This is why launch and 60-foot is so critical.  If you don't get that part quick, no amount of power or traction will make up for the other 1200 feet.

Also note that this is where I suck hardcore.  I'm way too timid - fear of redlighting, fear of breaking something, fear of losing traction, etc.

racerfink said:

preach (dudeist priest) said:

FWD bias, no AC, but I forever get told about windows up, no water box.

Coilovers: more stiff down rear and more stiff rebound on fronts?

Edit:I need to find out what torque my axles will hold...

You want weight transfer to the rear.  Look at any purpose built drag car at launch, and most times they are picking up at least one front wheel.  They run really soft springs in the rear with low bound settings trying to get as much weight over the rear axle as possible. Obviously you want to keep all four tires on the ground with AWD, but the rear tires are going to have more traction available with the weight shifting rearward at launch.  Also, are you running a lot of camber?  If you have a lot in the rear, when the car squats, you may only have an inch and a half of tire width touching the ground.

I would normally agree with that, but it seems counterintuitive depending on the AWD setup.  If you have a viscous case with a good bias, sure, but many of them have an open diff in the T-case which means shifting weight to the back will just let the front spin to the moon.

In reply to Curtis73 (Forum Supporter) :

No transfer case. Front wheels are locked to the output, rear wheels can get torque to the limit of the clutch pack.

I dunno about the Haldex in the R, but the one in my Volvo has a max torque capability of 1000 n-m, measured at the driveshaft. More than that and the clutches slip.  There is a 1500n-m unit available but I have a feeling that VW did not use the same rear diff as a V8 XC90.  Upshot is that (and it has been a while since I did the math) the rear tires can only transmit 100% of engine torque in 3rd gear and above.  In 1st and most of 2nd, at full throttle, if the front tires have zero traction, the clutches will slip.

That said!  At a dragstrip it is unlikely that the front tires will ever transmit zero torque unless you are pulling the tires off the ground  Practical experience, when my Haldex was inop thanks to a boating incident, I had no traction problems at the dragstrip thanks to how grippy the prepared surface is.  (14.6s at mid 100s in a 4000lb car, and righteous heat soak - IATs never went below 150, starting at 130!)

The story is mostly in your 60' times.

As noted above, ET is all in the launch.  Anyone putting up fast times is driving the car like they hate it. 1/2 second in the 60ft is a second at the big end.

I dug up some old records from a time I took our Subaru Legacy GT to the track about 15 years ago... AWD, turbo, similar power/weight (dynoed at ~290whp).

With a 1.9 60ft, I was running 13.50s @ 102.  This would have been on average street tires, with a handling biased suspension.  Just took it to the track a couple of times to see what it would do.  Getting the 60ft time under 2 seconds required a high rpm launch to get the car into boost and keep it from bogging.  Yes, I was worried about breaking things.  If I did an easier, 'sporty' launch the 60ft times went north of 2 seconds, and ETs went in the 14s.

Getting a good 60ft time out of a 3000lb car with a 4cyl turbo is going to require a HARD launch.  You just need to decided if your goal is to set ETs, and accept that carnage may result.

Your MPH does show a pretty wide spread.  I think you have your timesheets out of order looking at the time stamps.  It looks like you went 100, 105 and 103 mph.  That's a pretty wide spread, but there's 90 minutes between the first two and 60 minutes between 2-3.  If you're first run was pretty quick after getting there, the car may have been heat soaked from driving there.  Cooldown is very important, so get the hood up, and try not to idle much in the staging lanes.

As stated a couple times, 60' is EVERYTHING in drag racing.   Your best bet is to get out of the hole as quick as possible, and that needs to be practiced to get consistent.  It sets the stage for the rest of the track; time (and speed) lost here is multiplied down the rest of the track.    Curtis is also correct.   You DON'T want weight transfer in your car.   That is for RWD vehicles, and even then, the faster cars don't waste energy (which equals time) in the rear suspension.      Watch quick FWD and AWD cars and you won't see them lifting the front end.

 

C&D review of the car:

https://www.caranddriver.com/reviews/a15122740/2012-volkswagen-golf-r-us-spec-first-drive-review/

Assuming my Coils are set in the middle what would you do? Tighten compression in the rear and tighten rebound in the front for the strip? Try to keep it as neutral as possible.

I know I need seat time in it.

This feedback is great thank you all.

Wait until the Opel questions come out in a year of so.

Pete. (l33t FS) said:

MPH around 104 indicates about 300ish at the crank, assuming 3400lb.

I think a dyno operator was fudging numbers. You also probably got righteous heatsoak in the staging lanes, but not 150hp worth.

I think I will be paying the $175 for a awd base run on a hub dyno soon. Mitigated heat soak by resting between runs and killing engine in lanes. 2nd run we sat staged, engine off for about 30 mins due to a blown up C3 vette spewing oil.

In reply to preach (dudeist priest) :

Where is the IC on the R?

The Volvo has two intercoolers, one in front of the cooling stack and one between the A/C and radiator.  I had emptied the refrigerant so the computer would default the fans to high speed all the time, and the proximity to the radiator would still send temps right on up there without airflow through it (in either manner)

Having data is nice  Makes me really appreciate water/air systems, properly ducted for airflow.

In reply to Pete. (l33t FS) :

I have a Euro Audi S4 IC in the bumper with plenty of airway in anyways.

Keep in mind that magazine times are achieved by the driver having ZERO cares about breaking the car because it's not theirs. 

I'm hoping the clutch is upgraded in your car as the stock one gets unhappy with above stock power levels.

In reply to clutchsmoke :

Forgiving drag times I drive the thing hard, rolling thouhg.

Not enough though as I was worried about a 1-2-1 for lack of time.

Your coilovers and tires are killing your 60 ft times.  You are short shifting.  It's probably a low 13 sec car with more seat time.  12s will be hard without more power.  Unless the mph picks up a lot by shifting at 7000-7100, you won't run 12s.  Your fear of driving it hard is also killing your 60 ft times.  

Those 60ft times have to be 2 seconds or less for anything good to happen. This is obvious to drag vets from running a 14 flat but at 105mph with a 2.5 60ft. "Normal" 14 flat mph is 98-102. There was a 2.3 in there so there is hope with some changes. And a 14.5 at 103 is indicative of sufficient power available.